Abstract: The degree of diffusion of chloride in concrete is influenced by the stress. In this paper, chloride diffusion coefficients of C30 and C60 concretes are tested using conductivity method. The chloride permeability is evaluated according to CCES01-2004 Standard. Results show that the chloride permeability of C30 concrete is weaker than that of C60 concrete. The chloride permeability under tensile stress is stronger than that under compressive stress. Under compressive stress, as the stress ratio increases, the chloride diffusion coefficient decreases first and then increases. The chloride permeability is the lowest under stress ratio of 0.35. Under tensile stress, the chloride diffusion coefficient continuously increases with the increase in stress ratio, and when stress ratio reaches 0.35 it increases sharply. Under comprehensive consideration, when the stress ratio is 0.35 the chloride permeability is the lowest and it has minimal impact on the durability of concrete.

Key words: road engineering, chloride permeability, conductivity method, diffusion coefficient